[add] clear_function

src/App.vue

@@ -19,6 +19,7 @@ const elements = ref([
   "0",
   "+",
   "=",
+  "C",
 ]);
 
 const parameter = ref({
@@ -53,6 +54,10 @@ function onClick(e: any) {
     previous_result_value.value = "";
     operator.value = null;
   }
+
+  else if (e === "C") {
+    result_value.value = "";
+  }
 }